(svn r9026) [gamebalance] -Add: Added a new data type that allows fixed-point computations, as to enable computing non-integral numbers without worrying about the FPU rounding differences and, thus, desyncs. It is fully doxygenned, read the usage there. Thanks a bunch to KUDr for helping me with templates
--- a/Doxyfile Tue Mar 06 15:09:50 2007 +0000
+++ b/Doxyfile Tue Mar 06 15:30:54 2007 +0000
@@ -89,7 +89,7 @@
EXCLUDE =
EXCLUDE_SYMLINKS = NO
EXCLUDE_PATTERNS =
-EXAMPLE_PATH =
+EXAMPLE_PATH = docs/examples
EXAMPLE_PATTERNS = *
EXAMPLE_RECURSIVE = NO
IMAGE_PATH =
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/docs/examples/fixed_ex.cpp Tue Mar 06 15:30:54 2007 +0000
@@ -0,0 +1,22 @@
+/* $Id */
+
+#include "fixedt.h"
+
+int main()
+{
+ /* a is a Fixed-Point variable with 48 integral bits
+ * and 16 fractional bits, automatically set to zero
+ */
+ FixedT<int64, 16> a;
+
+ /* Assuming int is 32 bits, gives a variable of 23
+ * integral bits and 9 fractional bits, initialized
+ * to -4
+ */
+ FixedT<int, 9> b = -4;
+
+ /* A Variable set to a non-integral number
+ * in this case, -12.8
+ */
+ FixedT<long int, 12> c(-128, 10);
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/fixedt.h Tue Mar 06 15:30:54 2007 +0000
@@ -0,0 +1,303 @@
+/* $Id */
+
+/**
+ * @file
+ * Implements a Fixed-point data type.
+ * This files defines a new data type
+ * "FixedT<Tstorage, Tdec_bits>", which can be used to compute fractional
+ * numbers without having to worry about network stability (because
+ * there is no real rounding taking place.
+ * Use "Fixed" for the defaults values (48 bits integral part, 16 bits
+ * fractional part) or "FixedT<typename, int>" for flexible sizes. "int"
+ * number of bits are taken from a variable of "typename" for the fractional
+ * representation, the rest stays available for the integral part.
+ * @warning More than 16 bits fractional should not be used when working
+ * with large integers.
+ * @warning More than 31 fractional bits are not supported, and will
+ * trigger a compiler warning with appropriate settings.
+ * @warning There are no warnings for buffer overflows. Those are very likely
+ * to happen with divisions, as those first shift the numerator by the number
+ * of fractional bits. Use multiplication with the reciprocal whereever
+ * it is possible.
+ * @warning Please use signed variables for storage at the moment ONLY
+ *
+ * Variables can be initialized:
+ * - with integers: "FixedT<int, 9> a = -5"
+ * - with fractionals: "FixedT<int64, 11> b(7, 2);" where the first number is
+ * the numerator and the second is the denominator.
+ * - not at all: "Fixed c;", which will automatically set c to zero.
+ *
+ * @example fixed_ex.cpp How to initialize Fixed-point data types
+ */
+
+/* Included to overload the stream operator << */
+#include <iostream>
+/* Needed for some ottd-specific data types */
+#include "stdafx.h"
+
+/**
+ * Base Class for storing fixed-point data types.
+ * Fixed-point data types are stored in a single integer-type variable
+ * (Tstorage) of which a certain number of bits (Tdec_bits) is used to
+ * represent the fractional part of the number.
+ */
+template <typename Tstorage, int Tdec_bits>
+class FixedRawT {
+public:
+ /** The number of bits that represent the fractional */
+ static const int dec_bits = Tdec_bits;
+
+ /** The storage of the number itself */
+ Tstorage m_data;
+
+ /**
+ * Basic constructor for integer arguments.
+ * @param value The raw value to which we want to initialize
+ */
+ template <typename T>
+ FixedRawT(T value) : m_data(value) {}
+
+ /**
+ * Make sure that a Fixed variable is always inizialized to zero by default.
+ * We need this ctor so that we can declare variable without
+ * the need to initialize it explicitly
+ */
+ FixedRawT() : m_data (0) {}
+
+ /**
+ * Returns the biggest integral number we can represent
+ */
+ int64 FIXED_MAX() const { return m_maximum; }
+
+ /**
+ * Returns the biggest integral number we can represent
+ */
+ int64 FIXED_MIN() const { return m_minimum; }
+
+private:
+ /** The largest number we can hold */
+ static const int64 m_maximum = +(1ULL << ((sizeof(Tstorage) * 8) - Tdec_bits - 1)) - 1;
+
+ /** The smallest number we can hold */
+ static const int64 m_minimum = -(1ULL << ((sizeof(Tstorage) * 8) - Tdec_bits - 1)) - 0;
+};
+
+/* forward-declare some structs */
+template <typename Tstorage, int Tdec_bits> class FixedT;
+template <typename T> struct FixedHelperT;
+
+/**
+ * Specialization of FixedHelperT. Used to decimal-align two variables of Fixed type.
+ */
+template <typename Tstorage, int Tdec_bits> struct FixedHelperT<FixedRawT<Tstorage, Tdec_bits> >
+{
+ /** The number of bits used for the fraction */
+ static const int dec_bits = Tdec_bits;
+
+ /**
+ * Gives the raw data of a FixedRaw
+ * @param t The number to return
+ */
+ static int64 Raw(const FixedRawT<Tstorage, Tdec_bits>& t) {return (int64)t.m_data;}
+
+ /**
+ * Returns the data from FixedRawT aligned so that it is aligned to a given number
+ * @param t The number to be aligned
+ * @param bits The number of bits in the fractional part to be aligned to
+ */
+ static int64 Raw(const FixedRawT<Tstorage, Tdec_bits>& t, int bits)
+ {
+ return (((int64)t.m_data) << (bits > Tdec_bits ? bits - Tdec_bits : 0)) >> (bits < Tdec_bits ? Tdec_bits - bits : 0);
+ }
+};
+
+/**
+ * Specialization of FixedHelperT. Used to decimal-align two variables of Fixed type.
+ */
+template <typename Tstorage, int Tdec_bits> struct FixedHelperT<FixedT<Tstorage, Tdec_bits> > : public FixedHelperT<FixedRawT<Tstorage, Tdec_bits> > {};
+
+/**
+ * General implementation of FixedHelperT. This tempate makes sure that
+ * some number supplied is properly aligned at the decimal
+ */
+template <typename T> struct FixedHelperT
+{
+ /** This version of FixedHelperT is only used for full integers, so assume the number of dec_bits to be zero */
+ static const int dec_bits = 0;
+ /** Converts a full integer to one that has a given number of fractional bits, assumes
+ * the number of fractional bits to be zero.
+ * @param t the number to be converted
+ */
+ static int64 Raw(const T& t) {return (int64)t;}
+
+ /**
+ * Converts a full integer to one that has a given number of fractional bits
+ * @param bits the number of bits for the fraction
+ * @param t the number to be converted
+ */
+ static int64 Raw(const T& t, int bits) {return ((int64)t) << bits;}
+};
+
+
+
+/**
+ * A class that defines a fixed-point data type, which a variable length and precision.
+ * The data type that is defined is a fixed-point variable that has and number of Tdec_bits
+ * bits to represent the fractional part, the remaining bits of Tstorage are then used for
+ * the integer part of the number. This means, we always need to make a trade-off between
+ * the precision we want (higher number in Tdec_bits) and the range (smaller number of
+ * Tdec_bits). This class here only defines the constructors and the operators, everything
+ * else is happning in helper classes.
+ * @note for usage of fprintf and similar, explicit casts are needed (double or int64).
+ */
+template <typename Tstorage, int Tdec_bits> class FixedT : public FixedRawT<Tstorage, Tdec_bits> {
+/* private block up here, because we need the typedef later on */
+private:
+ /** We shortcut the underlying data type to "Raw", to save typing */
+ typedef FixedRawT<Tstorage, Tdec_bits> Raw;
+
+public:
+ /**
+ * Ctor for assignment with other, non floating, variable types
+ * @param value The Value we should assign to the Fixed
+ */
+ template <typename T> FixedT(T value) : Raw(FixedHelperT<T>::Raw(value, Tdec_bits)) {}
+
+ /** As a constructor without initializing, just use the one that Raw uses. Sets a variable to zero */
+ FixedT() : Raw() {}
+
+ /**
+ * Ctor for use with a fraction, useful for initing a variable to a non-integer number at declaration.
+ * @param numerator The Nominator of the fraction
+ * @param denominator The Denominator of the fraction
+ */
+ FixedT(int numerator, int denominator) {Raw::m_data = ((int64)numerator << Raw::dec_bits) / (int64)denominator;}
+
+ /**
+ * Equality operator
+ * @param comparator The non-floating point variable we want to compare against
+ */
+ template <typename T>
+ bool operator ==(const T &comparator) const { return Raw::m_data == (Tstorage)FixedHelperT<T>::Raw(comparator, Tdec_bits); }
+
+ /**
+ * Inequality operator
+ * @param comparator The non-floating point variable we want to compare against
+ */
+ template <typename T>
+ bool operator !=(const T &comparator) const { return Raw::m_data != (Tstorage)FixedHelperT<T>::Raw(comparator, Tdec_bits); }
+
+ /**
+ * Greater or equal operator
+ * @param comparator The non-floating point variable we want to compare against
+ */
+ template <typename T>
+ bool operator >=(const T &comparator) const { return Raw::m_data >= (Tstorage)FixedHelperT<T>::Raw(comparator, Tdec_bits); }
+
+ /**
+ * Less or equal operator
+ * @param comparator The non-floating point variable we want to compare against
+ */
+ template <typename T>
+ bool operator <=(const T &comparator) const { return Raw::m_data <= (Tstorage)FixedHelperT<T>::Raw(comparator, Tdec_bits); }
+
+ /**
+ * Greater than operator
+ * @param comparator The non-floating point variable we want to compare against
+ */
+ template <typename T>
+ bool operator >(const T &comparator) const { return Raw::m_data > (Tstorage)FixedHelperT<T>::Raw(comparator, Tdec_bits); }
+
+ /**
+ * Less than operator
+ * @param comparator The non-floating point variable we want to compare against
+ */
+ template <typename T>
+ bool operator <(const T &comparator) const { return Raw::m_data < (Tstorage)FixedHelperT<T>::Raw(comparator, Tdec_bits); }
+
+ /**
+ * Addition for Fixed-point data types
+ * @param value The non-floating point number to add
+ */
+ template <typename T> FixedT operator +(const T &value) const
+ {
+ return Raw(Raw::m_data + (Tstorage)FixedHelperT<T>::Raw(value, Tdec_bits));
+ }
+
+ /**
+ * Subtraction for Fixed-point data types
+ * @param value The non-floating point number to subtract
+ */
+ template <typename T> FixedT operator -(const T &value) const
+ {
+ return Raw(Raw::m_data - (Tstorage)FixedHelperT<T>::Raw(value, Tdec_bits));
+ }
+
+ /**
+ * A simple multiplication for non-floating data types
+ * @param value The non floating-point factor
+ */
+ template <typename T> FixedT operator *(const T &value) const
+ {
+ return Raw( (((int64)Raw::m_data) * FixedHelperT<T>::Raw(value)) >> FixedHelperT<T>::dec_bits);
+ }
+
+ /**
+ * A simple division for non-floating data types
+ * @param value The non floating-point divisor
+ */
+ template <typename T> FixedT operator /(const T &value) const
+ {
+ return Raw( (((int64)Raw::m_data) << FixedHelperT<T>::dec_bits) / FixedHelperT<T>::Raw(value));
+ }
+
+ /**
+ * Addition-assignment for Fixed-point data types
+ * @param value The non-floating point number to add
+ */
+ template <typename T> FixedT& operator +=(const T &value)
+ {
+ Raw::m_data = Raw::m_data + (Tstorage)FixedHelperT<T>::Raw(value, Tdec_bits);
+ return *this;
+ }
+
+ /**
+ * Subtract-assignment for Fixed-point data types
+ * @param value The non-floating point number to subtract
+ */
+ template <typename T> FixedT& operator -=(const T &value)
+ {
+ Raw::m_data = Raw::m_data - (Tstorage)FixedHelperT<T>::Raw(value, Tdec_bits);
+ return *this;
+ }
+
+ /**
+ * Multiply-assignment for Fixed-point data types
+ * @param value The non-floating point number to multiply
+ */
+ template <typename T> FixedT& operator *=(const T &value)
+ {
+ Raw::m_data = (Raw::m_data * (Tstorage)FixedHelperT<T>::Raw(value)) >> FixedHelperT<T>::dec_bits;
+ return *this;
+ }
+
+ /**
+ * Divide-assignment for Fixed-point data types
+ * @param value The non-floating point number to use as divisor
+ */
+ template <typename T> FixedT& operator /=(const T &value)
+ {
+ Raw::m_data = (Raw::m_data << FixedHelperT<T>::dec_bits) / (Tstorage)FixedHelperT<T>::Raw(value);
+ return *this;
+ }
+
+ /**
+ * Stream operator, used for floating point output
+ * @param os The stream we are going to write to
+ * @param value The Fixed-point variable we want to write in the stream
+ */
+ friend std::ostream& operator << (std::ostream &os, const FixedT &value) { os << (double)value.m_data / (1ULL << Raw::dec_bits); return os; }
+
+};
+
+